1. Field of the Invention
The present invention relates generally to battery chargers. More particularly, the present invention relates to a portable battery recharge station that can utilize a number of different portable power sources for recharging different types of secondary batteries of a variety of portable devices.
2. Background of the Invention
Many electrical appliances and electronic devices are portable. Specific examples of portable devices include wireless telephones, laptop computers, camcorders, pocket PCs, and toys. Some of these portable devices use primary batteries, e.g., alkaline batteries. Most of them, however, are powered by different types of rechargeable or secondary batteries. Examples of the types of secondary batteries include nickel-cadmium (NiCd), nickel-hydrogen (NiH2), nickel-metal hydride (NiMH), lithium ion (Li-ion), lithium polymer (Li-polymer), and lead acid batteries. Although zinc-air batteries have been widely used as primary batteries, they are also gaining popularity for use as secondary batteries.
Portable devices become disabled or inoperable when the power of their batteries drop below certain threshold. At that time, users of the portable devices must either replace depleted primary batteries with new primary batteries, or find a power source to recharge secondary batteries.
As known in the art, each portable device that uses a secondary battery is equipped with a unique charger dedicated to recharge the secondary battery. In other words, a typical consumer having three different types of portable devices may have three different battery chargers. For example, the consumer may have a first battery charger for his wireless telephone, a second battery charger for his camcorder, and a third battery charger for his Pocket PC. These three battery chargers are not interchangeable. In other words, the first battery charger may not be used for the camcorder or the Pocket PC. As a result, users of these battery chargers must carry all three chargers along with their portable devices. Accordingly, there is a need for a universal battery charger for multiple portable devices.
A typical secondary battery can be recharged using one of two power sources. For example, the typical secondary battery can be recharged by one battery charger adapted to receive energy from an electrical wall outlet. In addition, the typical secondary battery can be recharged by another battery charger adapted to receive electrical energy from a cigarette lighter outlet of an automobile. There are many situations in which neither of the power sources is available. For example, an explorer who is out in the field for days or weeks at a time may endanger himself when his wireless communication device becomes inoperable due to a depleted battery. Similarly, a news crew member can lose valuable opportunities when its camcorder runs out of battery during an important news coverage at a place where no power source is available. Accordingly, there is a need for a portable battery recharge station that can recharge secondary batteries with a portable power source.
There are a number of battery chargers known in the art. For example, U.S. Pat. No. 5,343,136 (the xe2x80x9cYamaguchi patentxe2x80x9d) discloses a charger having a chargeable battery with a larger current capacity than a target chargeable battery of a cordless telephone. The charger disclosed can only be used to recharge its associated target chargeable battery.
U.S. Pat. No. 5,396,162 (the xe2x80x9cBrilmyer patentxe2x80x9d) discloses a portable battery charger that utilizes an assembly of primary battery cells to recharge the rechargeable battery of a battery appliance. The portable battery charger disclosed is limited to using primary battery cells as its portable power source.
U.S. Pat. No. 5,565,756 (the xe2x80x9cUrbish patentxe2x80x9d) discloses a microprocessor controlled portable battery charger for use with a variety of battery packs. The charger disclosed can use either primary or secondary batteries as its portable power source. The charger requires charging, sensing, identifying, and output means to properly recharge the battery packs.
U.S. Pat. No. 6,154,007 (the xe2x80x9cShaver patentxe2x80x9d) discloses a battery charging system that enables rapid recharging of a working battery without the need for current limit and/or over-voltage protection. The portable battery charging system disclosed, however, must always have a greater number of cells than the number of cells in the working battery.
Various technologies related to rechargeable batteries are further disclosed in other U.S. Patents. For example, U.S. Pat. Nos. 5,747,968 and 5,773,959 (the xe2x80x9cMerritt patentsxe2x80x9d) disclose lithium polymer battery charging methods and apparatus. U.S. Pat. No. 5,645,960 (the xe2x80x9cScrosati patentxe2x80x9d) discloses a thin film lithium polymer battery. U.S. Pat. Nos. 6,091,230 and 6,166,548 (the xe2x80x9cWinzer patentsxe2x80x9d) discloses a voltage recovery method for a zinc-air battery and a method of detecting battery capacity of a zinc-air battery, respectively. U.S. Pat. No. 6,146,781 (the xe2x80x9cSurampudi patentxe2x80x9d) discloses a direct methanol feed fuel cell and system. U.S. Pat. No. 5,352,967 (the xe2x80x9cKarl-Diether patentxe2x80x9d) discloses a charging method for NiCd and NiH cells. U.S. Pat. No. 6,043,631 (the xe2x80x9cTsenter patentxe2x80x9d) discloses a method for charging NiCd, NiH2 and NiMH batteries.
Each of the above-referenced U.S. patents is incorporated herein by reference in its entirety.
The present invention is a system and method for recharging secondary batteries. One embodiment of the present invention is a portable battery recharge station. The recharge station comprises a supervisory circuit, a voltage converter, a portable power source, and at least one holder that is adapted to receive a specific type of secondary battery of a portable device.
In this embodiment, when a secondary battery is placed in the holder, the supervisory circuit that is connected to the holder communicates with the voltage converter to supply an appropriate voltage required to recharge the secondary battery. The voltage converter receives electrical power from the portable power source. The voltage converter can convert the voltage of the portable power source up (i.e., increasing the voltage) or down (i.e., decreasing the voltage) as appropriate to recharge the secondary battery as instructed by the supervisory circuit.
The portable power source of the portable battery recharge station can be one of several types of power sources. For example, the portable power source can be replaceable, rechargeable, or renewable. Replaceable power source can comprise a primary battery. Examples of primary batteries are alkaline and zinc-air batteries. When a primary battery is depleted, it is removed from the portable battery recharge station and replaced by a fresh or new primary battery.
A rechargeable power source can comprise a secondary battery. Examples of secondary batteries include NiCd, NiH2, NiMH, Li-ion, Li-polymer, and zinc-air batteries. A depleted secondary battery can be recharged by an external power source through a recharger of the portable battery recharge station.
A renewable power source can comprise a renewable battery. Examples of renewable batteries include a methanol fuel cell and other fuel cell whose electrolyte can be replenished or otherwise replaced. When a renewable battery is depleted, an appropriate fuel can be added or old electrolyte can be renewed to supply energy to the portable power source. For example, zinc electrolyte cells can be renewed by replacing the electrolyte in the cell.
Preferably, the portable battery recharge station has more than one holder. Each holder can be adapted to receive a specific type of secondary battery. For example, a first holder can be adapted to receive a Nixe2x80x94Cd battery, a second holder can be adapted to receive a NiMH battery, a third holder can be adapted to receive a Li-ion battery, a fourth holder can be adapted to receive a Li-polymer battery, and so on. The holders must be designed to accommodate the physical dimensions of the battery, as well as the placement of the contacts on the battery. Optionally, some of the battery holders may be modified with exchangeable plates designed to accommodate different battery dimensions and contact placements. The supervisory circuit connected to the holders can detect which holder or holders have received a secondary battery. The supervisory circuit can then inform the voltage converter to supply an appropriate voltage to each of the holders that has received a secondary battery. Of course, different batteries (e.g., a NiCd and a Li-ion battery) having the same dimensions could be used with the same holder, because the supervisory circuit can detect the appropriate voltage required for the battery.
In another embodiment, the present invention is a battery charging system comprising a portable battery recharge station and a device-specific charging cord. The portable battery recharge station of this embodiment has a universal connector socket in addition to or in lieu of the holder described above. The universal connector socket is adapted to mate with a universal connector plug that is on one end of the device-specific charging cord. The universal connector plug comprises a programming resistor that identifies the type of secondary battery that is used by a portable device associated with the device-specific charging cord. The other end of the device-specific charging cord has a device-specific charge connector that is adapted to mate with a normal device charger connector of the portable device. Preferably, the portable battery recharge station has more than one universal connector socket so that multiple secondary batteries of a plurality of portable devices can be recharged concurrently.
Accordingly, it is an object of the present invention to provide a portable battery recharge station that can recharge different types of secondary batteries of various portable devices.
It is another object of the present invention to provide a portable battery recharge station that can use a variety of portable power sources.
It is another object of the present invention to provide a portable battery recharge station than can recharge two or more types of secondary batteries concurrently.
These and other objects of the present invention are described in greater detail in the detailed description of the invention, the appended drawings, and the attached claims.